Legitimate concern. Are you aware of the death of the Forest Service cop outside of Glacier N.P. in 2016? He did exactly that and was mauled. From what they would tell, he was bombing a descent on his MTB, came around a corner and hit the bear. Estimate was that he had between 1 and 3 seconds to react after seeing the creature. His brother-in-law was behind him and came upon the scene, but there was nothing he could do.